From c50cd357887acf9fd7af3a5d492911bd825555a2 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Mon, 1 Jul 2013 19:24:00 +0200 Subject: net: gre: move GSO functions to gre_offload Similarly to TCP/UDP offloading, move all related GRE functions to gre_offload.c to make things more explicit and similar to the rest of the code. Suggested-by: Eric Dumazet Signed-off-by: Daniel Borkmann Signed-off-by: David S. Miller --- net/ipv4/gre_demux.c | 414 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 414 insertions(+) create mode 100644 net/ipv4/gre_demux.c (limited to 'net/ipv4/gre_demux.c') diff --git a/net/ipv4/gre_demux.c b/net/ipv4/gre_demux.c new file mode 100644 index 000000000000..736c9fc3ef93 --- /dev/null +++ b/net/ipv4/gre_demux.c @@ -0,0 +1,414 @@ +/* + * GRE over IPv4 demultiplexer driver + * + * Authors: Dmitry Kozlov (xeb@mail.ru) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include + +static const struct gre_protocol __rcu *gre_proto[GREPROTO_MAX] __read_mostly; +static struct gre_cisco_protocol __rcu *gre_cisco_proto_list[GRE_IP_PROTO_MAX]; + +int gre_add_protocol(const struct gre_protocol *proto, u8 version) +{ + if (version >= GREPROTO_MAX) + return -EINVAL; + + return (cmpxchg((const struct gre_protocol **)&gre_proto[version], NULL, proto) == NULL) ? + 0 : -EBUSY; +} +EXPORT_SYMBOL_GPL(gre_add_protocol); + +int gre_del_protocol(const struct gre_protocol *proto, u8 version) +{ + int ret; + + if (version >= GREPROTO_MAX) + return -EINVAL; + + ret = (cmpxchg((const struct gre_protocol **)&gre_proto[version], proto, NULL) == proto) ? + 0 : -EBUSY; + + if (ret) + return ret; + + synchronize_rcu(); + return 0; +} +EXPORT_SYMBOL_GPL(gre_del_protocol); + +void gre_build_header(struct sk_buff *skb, const struct tnl_ptk_info *tpi, + int hdr_len) +{ + struct gre_base_hdr *greh; + + skb_push(skb, hdr_len); + + greh = (struct gre_base_hdr *)skb->data; + greh->flags = tnl_flags_to_gre_flags(tpi->flags); + greh->protocol = tpi->proto; + + if (tpi->flags&(TUNNEL_KEY|TUNNEL_CSUM|TUNNEL_SEQ)) { + __be32 *ptr = (__be32 *)(((u8 *)greh) + hdr_len - 4); + + if (tpi->flags&TUNNEL_SEQ) { + *ptr = tpi->seq; + ptr--; + } + if (tpi->flags&TUNNEL_KEY) { + *ptr = tpi->key; + ptr--; + } + if (tpi->flags&TUNNEL_CSUM && + !(skb_shinfo(skb)->gso_type & SKB_GSO_GRE)) { + *ptr = 0; + *(__sum16 *)ptr = csum_fold(skb_checksum(skb, 0, + skb->len, 0)); + } + } +} +EXPORT_SYMBOL_GPL(gre_build_header); + +struct sk_buff *gre_handle_offloads(struct sk_buff *skb, bool gre_csum) +{ + int err; + + if (likely(!skb->encapsulation)) { + skb_reset_inner_headers(skb); + skb->encapsulation = 1; + } + + if (skb_is_gso(skb)) { + err = skb_unclone(skb, GFP_ATOMIC); + if (unlikely(err)) + goto error; + skb_shinfo(skb)->gso_type |= SKB_GSO_GRE; + return skb; + } else if (skb->ip_summed == CHECKSUM_PARTIAL && gre_csum) { + err = skb_checksum_help(skb); + if (unlikely(err)) + goto error; + } else if (skb->ip_summed != CHECKSUM_PARTIAL) + skb->ip_summed = CHECKSUM_NONE; + + return skb; +error: + kfree_skb(skb); + return ERR_PTR(err); +} +EXPORT_SYMBOL_GPL(gre_handle_offloads); + +static __sum16 check_checksum(struct sk_buff *skb) +{ + __sum16 csum = 0; + + switch (skb->ip_summed) { + case CHECKSUM_COMPLETE: + csum = csum_fold(skb->csum); + + if (!csum) + break; + /* Fall through. */ + + case CHECKSUM_NONE: + skb->csum = 0; + csum = __skb_checksum_complete(skb); + skb->ip_summed = CHECKSUM_COMPLETE; + break; + } + + return csum; +} + +static int parse_gre_header(struct sk_buff *skb, struct tnl_ptk_info *tpi, + bool *csum_err) +{ + unsigned int ip_hlen = ip_hdrlen(skb); + const struct gre_base_hdr *greh; + __be32 *options; + int hdr_len; + + if (unlikely(!pskb_may_pull(skb, sizeof(struct gre_base_hdr)))) + return -EINVAL; + + greh = (struct gre_base_hdr *)(skb_network_header(skb) + ip_hlen); + if (unlikely(greh->flags & (GRE_VERSION | GRE_ROUTING))) + return -EINVAL; + + tpi->flags = gre_flags_to_tnl_flags(greh->flags); + hdr_len = ip_gre_calc_hlen(tpi->flags); + + if (!pskb_may_pull(skb, hdr_len)) + return -EINVAL; + + greh = (struct gre_base_hdr *)(skb_network_header(skb) + ip_hlen); + tpi->proto = greh->protocol; + + options = (__be32 *)(greh + 1); + if (greh->flags & GRE_CSUM) { + if (check_checksum(skb)) { + *csum_err = true; + return -EINVAL; + } + options++; + } + + if (greh->flags & GRE_KEY) { + tpi->key = *options; + options++; + } else + tpi->key = 0; + + if (unlikely(greh->flags & GRE_SEQ)) { + tpi->seq = *options; + options++; + } else + tpi->seq = 0; + + /* WCCP version 1 and 2 protocol decoding. + * - Change protocol to IP + * - When dealing with WCCPv2, Skip extra 4 bytes in GRE header + */ + if (greh->flags == 0 && tpi->proto == htons(ETH_P_WCCP)) { + tpi->proto = htons(ETH_P_IP); + if ((*(u8 *)options & 0xF0) != 0x40) { + hdr_len += 4; + if (!pskb_may_pull(skb, hdr_len)) + return -EINVAL; + } + } + + return iptunnel_pull_header(skb, hdr_len, tpi->proto); +} + +static int gre_cisco_rcv(struct sk_buff *skb) +{ + struct tnl_ptk_info tpi; + int i; + bool csum_err = false; + + if (parse_gre_header(skb, &tpi, &csum_err) < 0) + goto drop; + + rcu_read_lock(); + for (i = 0; i < GRE_IP_PROTO_MAX; i++) { + struct gre_cisco_protocol *proto; + int ret; + + proto = rcu_dereference(gre_cisco_proto_list[i]); + if (!proto) + continue; + ret = proto->handler(skb, &tpi); + if (ret == PACKET_RCVD) { + rcu_read_unlock(); + return 0; + } + } + rcu_read_unlock(); + + icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0); +drop: + kfree_skb(skb); + return 0; +} + +static void gre_cisco_err(struct sk_buff *skb, u32 info) +{ + /* All the routers (except for Linux) return only + * 8 bytes of packet payload. It means, that precise relaying of + * ICMP in the real Internet is absolutely infeasible. + * + * Moreover, Cisco "wise men" put GRE key to the third word + * in GRE header. It makes impossible maintaining even soft + * state for keyed + * GRE tunnels with enabled checksum. Tell them "thank you". + * + * Well, I wonder, rfc1812 was written by Cisco employee, + * what the hell these idiots break standards established + * by themselves??? + */ + + const int type = icmp_hdr(skb)->type; + const int code = icmp_hdr(skb)->code; + struct tnl_ptk_info tpi; + bool csum_err = false; + int i; + + if (parse_gre_header(skb, &tpi, &csum_err)) { + if (!csum_err) /* ignore csum errors. */ + return; + } + + if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) { + ipv4_update_pmtu(skb, dev_net(skb->dev), info, + skb->dev->ifindex, 0, IPPROTO_GRE, 0); + return; + } + if (type == ICMP_REDIRECT) { + ipv4_redirect(skb, dev_net(skb->dev), skb->dev->ifindex, 0, + IPPROTO_GRE, 0); + return; + } + + rcu_read_lock(); + for (i = 0; i < GRE_IP_PROTO_MAX; i++) { + struct gre_cisco_protocol *proto; + + proto = rcu_dereference(gre_cisco_proto_list[i]); + if (!proto) + continue; + + if (proto->err_handler(skb, info, &tpi) == PACKET_RCVD) + goto out; + + } +out: + rcu_read_unlock(); +} + +static int gre_rcv(struct sk_buff *skb) +{ + const struct gre_protocol *proto; + u8 ver; + int ret; + + if (!pskb_may_pull(skb, 12)) + goto drop; + + ver = skb->data[1]&0x7f; + if (ver >= GREPROTO_MAX) + goto drop; + + rcu_read_lock(); + proto = rcu_dereference(gre_proto[ver]); + if (!proto || !proto->handler) + goto drop_unlock; + ret = proto->handler(skb); + rcu_read_unlock(); + return ret; + +drop_unlock: + rcu_read_unlock(); +drop: + kfree_skb(skb); + return NET_RX_DROP; +} + +static void gre_err(struct sk_buff *skb, u32 info) +{ + const struct gre_protocol *proto; + const struct iphdr *iph = (const struct iphdr *)skb->data; + u8 ver = skb->data[(iph->ihl<<2) + 1]&0x7f; + + if (ver >= GREPROTO_MAX) + return; + + rcu_read_lock(); + proto = rcu_dereference(gre_proto[ver]); + if (proto && proto->err_handler) + proto->err_handler(skb, info); + rcu_read_unlock(); +} + +static const struct net_protocol net_gre_protocol = { + .handler = gre_rcv, + .err_handler = gre_err, + .netns_ok = 1, +}; + +static const struct gre_protocol ipgre_protocol = { + .handler = gre_cisco_rcv, + .err_handler = gre_cisco_err, +}; + +int gre_cisco_register(struct gre_cisco_protocol *newp) +{ + struct gre_cisco_protocol **proto = (struct gre_cisco_protocol **) + &gre_cisco_proto_list[newp->priority]; + + return (cmpxchg(proto, NULL, newp) == NULL) ? 0 : -EBUSY; +} +EXPORT_SYMBOL_GPL(gre_cisco_register); + +int gre_cisco_unregister(struct gre_cisco_protocol *del_proto) +{ + struct gre_cisco_protocol **proto = (struct gre_cisco_protocol **) + &gre_cisco_proto_list[del_proto->priority]; + int ret; + + ret = (cmpxchg(proto, del_proto, NULL) == del_proto) ? 0 : -EINVAL; + + if (ret) + return ret; + + synchronize_net(); + return 0; +} +EXPORT_SYMBOL_GPL(gre_cisco_unregister); + +static int __init gre_init(void) +{ + pr_info("GRE over IPv4 demultiplexor driver\n"); + + if (inet_add_protocol(&net_gre_protocol, IPPROTO_GRE) < 0) { + pr_err("can't add protocol\n"); + goto err; + } + + if (gre_add_protocol(&ipgre_protocol, GREPROTO_CISCO) < 0) { + pr_info("%s: can't add ipgre handler\n", __func__); + goto err_gre; + } + + if (gre_offload_init()) { + pr_err("can't add protocol offload\n"); + goto err_gso; + } + + return 0; +err_gso: + gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO); +err_gre: + inet_del_protocol(&net_gre_protocol, IPPROTO_GRE); +err: + return -EAGAIN; +} + +static void __exit gre_exit(void) +{ + gre_offload_exit(); + + gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO); + inet_del_protocol(&net_gre_protocol, IPPROTO_GRE); +} + +module_init(gre_init); +module_exit(gre_exit); + +MODULE_DESCRIPTION("GRE over IPv4 demultiplexer driver"); +MODULE_AUTHOR("D. Kozlov (xeb@mail.ru)"); +MODULE_LICENSE("GPL"); -- cgit v1.2.3-59-g8ed1b